Fastener assembly



Jan. 31, 1961 D. H. GILL FASTENER ASSEMBLY Filed April 24, 1959 IN VENTOR. fla/zvZJ/k QZ/ AT TOR/V5 Y United States Pateiit 2 97 2 FASTENERASSEMBLY Dali a Gi S -.Ijclair. S i l h-ia iti r "er'aLMotorsCbrjioratidmDetroit, Micln, a corporation ofDelaware A p H Filed Apr.'24, an, as. N6. met 2 claims. 01. 339 1 1) This invention relates ,,tofastener assemblies, and more particularly to an electricallyconductingground strap for use with a plasticnanchor.nutm. In many fastenerinstallations in..which an electrical fixture. maynbenslecuredttoasupporting plate, little or no provisions, are made for electricallygrounding the electrical fixturej with. respect to the remainder of theassembly. In. many installations.nonaconducting materials are used forthe, fastenermembers, because of their relative inexpensiveness ascompared to metallic fasteners; and it is easily seen thatif, a plasticfastener member is non-conducting, no grounding provisions are provided.The device-in which this invention is embodied comprises generallyastaple-like strap member which may be used with a plastic, orsotherwisenon-conducting, fastener member in an,,installation wherein anelectrical fixture is secured to a motor vehicle supporting panel. Suchan installation might be the securing of a vehicle front parking lamp tothe vehicle front fender. In such an installation, the electricalfixture is secured to the supporting panel by a plastic nut member and ametallic bolt; receivable in thenut member and adapted to retain the nutmember in the sup-portingpanel. In this type. of installation, no partof the metallic bolt member touches the supporting panel to provide thenecessary ground connection between the electrical fixture and thesupporting panel. The proposed staple-like ground strap is provided withtabs which bite into the surfaces of the electrical fixture and thesupporting panel in such a manner as to provide a positive groundcontact between the two parts. The device is relatively simple andinexpensive to manufacture and may be used with existing fasteners toprovide suitable volume production grounding means.

In the drawings:

Figure l is a view of the fastener assembly with parts broken away andin section to illustrate the location of the various parts.

Figure 2 is a cross-sectional view of the assembly illustrated in Figure1 taken substantially along the line 2-2 of Figure l and looking in thedirection of the arrows.

Figure 3 is a cross-sectional view of the assembly shown in Figure 1taken substantially along the line 3-3 and looking in the direction ofthe arrows.

Figure 4 is an isometric view of the electrical ground strap illustratedin Figure 1.

Figure 5 is a modification of the fastener assembly of Figure 1.

Figure 6 is an isometric view of the electrical ground strap used in themodification of Figure 5.

Referring more particularly to the drawings, Figures 1 through 4illustrate a modification of the fastener assembly in which a supportingplate 10 is to receive a flange 12 of an electrical fixture, such as avehicle parking lamp. The supporting panel 10 has, in this instance, asquare aperture 14 therein to receive the fastener mem- 2,970,287 UPatented Jan. 31,1961

her. The flange 1 2 hasa cylindrical aperture 16 formed therein toreceive the shank of a suitable bolt.

In properly assembling the flange 12 to the. supporting panel 10, it isnecessary to have a certain amount of clearance therebetween. The nutmember, illustrated generally by the numeral: 18; provides a means forreceiving the fastening bolt, illustrated generally by the numeral 20,and at the same-time spaces the flange 12 from the supporting panel 10.The nut member 18 has a cylindrical head portion 22 and a prismaticshank portion 24. The prismatic shank portion extends through the squareaperture 14 in the supporting panel, to prevent rotation of the nutmember in the supporting-panel when the bolt is tightened. The'headportion 22 and shank portion 24- have a central bolt receiving opening26 axially formed along the length thereof, the opening being taperedtoward the end of the shank portion within that portion. I I t p lTwosides of the prismatic shank portion are provided with longitudinaltriangular slots 28, allowing the two portions ofthe shank portiontospread when the bolt 20 is inserted therein. shoulder 39, formed onthe split sides of the shank member, allows the shank tobe insertedinthe square aperture 14 on assembly and, when the bolt 20 is insertedtherein, expand to a size greater than the square aperture 14 to preventinadvertent removal of the fastener 18 from the supporting plate 10.

The head portion 22 of the nut member 18 has a plu: rality of axialopenings 32 formed part way therethrough and circular openings 34. inthe bottom of each aperture 32. extending the remainder ofthe waythrough the head. The apertures 32 are s eparated by a plurality of webs36, extending between the outer rim '38 of the head member and the innerrim 40 about the-bolt receiving opening. The purpose of the apertures 32and openings 34-will be later described. I g The bolt member 20 includesa standard head portion 42 with an annular. flange 44 extendingtherefrorn to form a better retaining surface for the flange 12.Extending from the head 42 and annular flange 44 is the bolt shank 46,threaded along a portion of its length, as at 48. The threads are soformed that they will cut their own corresponding thread in the shank 24of the nut member 18, upon the usual rotation in a tightening direction.It may be seen that by tightening the bolt 20 within the head portionand shank portion of the nut member 18 that the shank 24 of the nutmember will expand due to the tapered opening, to prevent the nut memberfrom pulling away from the supporting panel 10, because of the shoulder30. At the same time, the nut and bolt will pull the supporting panel 10toward the flange 12, or vice versa.

In order to provide the proper ground contact between the flange 12 andthe supporting panel 10, a staple-like strap member, illustratedgenerally by the numeral 50, is provided between the head portion 22 andthe flange 12. The strap is best illustrated in Figure 4, where it isshown to have a U-shaped body portion, with a base member 52 and legmembers 54 extending at right angles therefrom. A central aperture 56receives the shank 46 of the bolt 20. A sharp pointed tab 58 is formedon the end of each leg 54, and a pair of tabs 60, also pointed, areformed from the surface of the base portion 52 in a direction away fromthe legs 54.

Referring again to Figure 1, it may be seen that if the strap member issecured in the assembly, the legs 54 will be received in the apertures32 in the head portion 22 and the pointed tabs 58 extend through theholes 34 in the bottom of the apertures 32. The pointed tabs are of suchlength that they will bite into the surface of the supporting panel 10,upon tightening of the assembly through the bolt 20, and the pointedtabs 60 will at the same time bite into' the surface of the flange 12.Thus, a positive electrical connection is made between the supportingpanel 10 and the flange 12.

A modification of the device is illustrated in Figures 5 and 6, in whichthe supporting panel and flange 12 are secured by the nut member 62 andthe bolt 20. The nut member 62 may have a solid head portion 64, withthe exception of the central bolt receiving aperture extending throughthe head portion 64 and the shank portion 66. The ground strap,illustrated generally by the numeral 68, is again U-shaped, having aflat base portion 70 and a pair of arcuate leg portions 72 and 74. Thebolt receiving aperture 76 provides a means for retaining the groundstrap, with respect to the nut and bolt assembly. In order to positivelycontact the supporting panel 10, the arcuate leg 72 of the strap memheris provided with a pair of points 78, formed by making an arcuate cut 80in the leg member. A pair of tabs 82 are formed on the sides of the legportion 72 and are adapted to bear against the head portion 64 of thenut member 62 when the assembly is made. The tabs or barbs 82 preventthe inadvertent removal of the ground strap 68 from the nut member 62.The opposite leg member 74 is formed with a single point 84 for positivecontact with the support panel 10 and the barbs 82 on the leg 72 providegrip-ping contact with the head portion 64 of the nut member 62. Aplurality of sharp points 86 are provided in the base surface of theground strap to provide a positive contact with the flange 12. When theassembly is complete, the ground strap extends between the fiange 12 andthe supporting panel 10, and outside of the head portion 64 of the nutmember .62, to establish electrical ground contact through the sharppoints 86 and the sharp points 78 and 84 which of said panels; said nutmember including a shank portion receivable in an aperture in said onepanel, a head portion extending radially from said shank portion andhaving a plurality of apertures therethrough, said head portion and saidshank portion having a central bolt receiving opening therethrough; andsaid ground strap 2. A fastener and ground strap assembly comprising anut member having a head portion and a shank portion, said shank portionbeing receivable in a first panel, a bolt member receivable in said nutmember and retaining said shank portion in said panel, said bolt memberbeing receivable in a second panel such that said second panel issecured in relative spaced relation with respect to said first panel,said head portion lying between said first and second panels when in anassembled position, and a U-shaped metallic member receivable on saidbolt member and having the base portion thereof between said secondpanel and said nut member and positively engaging said second panel,said head portion having a plurality of apertures therethrough toreceive the legs of said U-shaped member, tabs extending from the endsof the leg portions of said U-shaped member and positively engaging saidfirst panel member to provide an electrical connection between saidfirst and second panel members.

References (Zited in the file of this patent UNITED STATES PATENTSElliott June 29, 1954

